1. Field of the Invention
The present invention relates to a milking parlour and a method for operating the same and particularly, but not exclusively, to a rotary milking parlour for milking an animal, such as a cow, and to a method for operating the same.
2. Description of the Related Art
There are various types of milking parlour known in the dairy industry and the present invention is of particular relevance to what is commonly referred to as a rotary milking parlour. This type of parlour is provided with a comparatively large number of milking stalls arranged in a circular configuration on a rotating annular platform and is of particular use in handling a large number of animals. The platform rotates at a relatively low constant speed so that a cow may readily step onto the platform from a stationary holding bay and thereby gain access to a stall. If deemed necessary by an operator, the rotary movement of the platform may be stopped momentarily in order to allow a cow sufficient time to enter (or exit) the platform. The continued rotation of the platform then moves the stall into a position where an operator can perform certain tasks (such as teat cleaning and placement of teat cups on the teats) so as to allow the milking process to begin. The speed of rotation is such that the milking process will have been completed by the time a stall has moved from the cow entry position (where a cow gains entry onto the platform) to a cow exit position (where a cow is permitted to leave the platform). The cow entry and exit points are adjacent one another so as to maximise the time a cow spends in the milking stall.
It will be understood that cows may constantly enter and exit a rotary parlour without necessarily stopping the platform rotation and this allows for a large number of cows to be handled. It will be also understood that the movement of the platform results in cows being brought to an operator in turn. The operator is therefore able to remain in one location and concentrate on essential milking tasks without interruptions.
There are two main types of rotary milking parlour system, which may be referred to, as the Parallel Rotary system and the Herringbone Rotary system.
In a Herringbone Rotary system, a cow stands in a stall facing diagonally towards the outside of an annular rotating platform, in the general direction of rotation. One or more operators stand on the inside of the rotating platform and are thereby provided good access to the side of each cow. Milking equipment is positioned alongside each cow on the inside edge of the platform.
In a Parallel Rotary system, a cow stands in a stall of a rotating platform so as to face radially inward towards the centre of rotation of the platform. Operators stood outside the rotating platform are then able to work from the rear of each cow as the cow passes in turn. Because the cows are positioned side by side, the parallel rotary system allows more cows to be accommodated in the same space.
In each of these types of rotary parlour, each milking stall is provided with a cluster of four teat cups. These teat cups are attached to the teats of a cow located within the stall so as to allow said cow to be milked. Once the milking process has been completed, an automatic retraction system is typically used to remove the four teat cups simultaneously from the teats. Such a system comprises a cord which is attached to the teat cup cluster and which is retracted automatically at an appropriate time so as to pull the teat cup cluster from the cow.
A problem associated with rotary milking parlours is that an operator only has a limited amount of time in which to service a milking stall before the milking stall moves beyond the reach of the operator. An operator may service a milking stall in a number of ways, for example, an operator will typically service a milking stall by moving teat cups from a storage position into a position where they are attached to the teats of a cow stood within the milking stall. Although a teat cup cluster will be typically attached to the teats of a cow before the milking stall has moved a significant distance, unpredictable events such as movement by an unsettled cow can significantly delay the teat cup attachment process. This is not necessarily problematic when a human operator services the milking stalls because the operator can walk with the rotating platform and remain with the particular stall experiencing the delay. However, delays in servicing a stall can be problematic in circumstances where a robot arm is being used for the servicing activity. This is because the robot arm has a fixed position within a milking parlour and so a milking stall will tend to move quite rapidly beyond its reach. This problem is also a particular issue when the speed of the milking stalls is comparatively high. This may be found in large rotary parlours where the linear tangential speed of a stall will be comparatively high for a given angular speed because of the comparatively large platform radius.